Electrical workers such as linemen use grounding cables to help manage dangerous voltages and currents in de-energized power lines and electrical equipment. Ground clamps, which are used to make the grounding connection, are intended to be installed and removed using an insulating tool, for example an insulating tool called a Grip-All™ stick or Shotgun or hot-stick, to keep the worker at a safe distance from the electrical hazard.
When installing grounds, the first connection is always made to a ground point. Workers will normally make this connection by hand, rather than with an insulating tool, as there is no hazardous energy when making this connection.
Any time a connection is made to a conductor or apparatus that could be at a different electrical potential from the ground, this connection must be made using an insulating tool. This is especially true in a high voltage environment; for example, in excess of 69 kV. However, due to the design of conventional ground clamps, they may be installed and removed by hand rather than by using an insulating tool. It is not uncommon, in the applicant's experience, for workers to make the mistake of installing a ground clamp on a conductor, or removing one from a conductor by hand, rather than using an insulating tool. This may expose the worker to a voltage potential and may result in electrocution of the worker. To the applicant's knowledge, installing or removing a ground clamp by hand has resulted in electrocution incidents and fatalities in the industry.
Consequently, there is a need in the industry for a locking ground clamp that only operates in combination with an insulating tool, so as to prevent the worker or lineman from being able to operate the ground clamp without the use of the insulating tool. This is to inhibit workers or linemen from attempting to install or remove the grounding clamp by hand.